Blower

ABSTRACT

The invention is based on a blower having a rotatable gas delivery means ( 10 ).  
     It is proposed that the gas delivery means ( 10 ) comprise a mass distribution that generates a predefined torque perpendicular to the axis of rotation ( 26 ) when the gas delivery means ( 10 ) rotates.

RELATED ART

[0001] The invention is based on a blower according to the preamble of claim 1.

[0002] Numerous embodiments of blowers forming the generic class are known and are used for cooling, heating, or ventilation. Ventilators, fan wheels, or turbines are used as rotatable gas delivery means. As a rule, fan wheels are used in engine radiator blowers. Disturbing noises are produced by internal combustion engine radiator blowers as a result of first-order excitation of vibrations that are transmitted into a passenger compartment as air-borne or structure-borne noise, and impair driving smoothness. Presently, these noises are kept to a minimum by means of single-plane balancing of the fully-assembled internal combustion engine radiator blower, i.e., by balancing the static imbalance. The static imbalance is thereby balanced manually using balancing clamps. Although radial runout caused by imbalance and, therefore, noise formation caused by untrue running can be prevented in fan wheels balanced in this fashion, the fan wheel can move back and forth between its two bearing end positions within the scope of its bearing clearance.

ADVANTAGES OF THE INVENTION

[0003] The invention is based on a blower having a rotatable gas delivery means.

[0004] It is proposed that the gas delivery means comprises a mass distribution that generates a predefined torque perpendicular to the axis of rotation when the gas delivery means rotates. If torque in the center of gravity acts upon the gas delivery means perpendicular to the axis of rotation, the gas delivery means is tilted downward within the scope of its bearing clearance. This can prevent the gas delivery means from moving freely within the bearing clearance and thrashing back and forth between the end positions of the bearing. A bracing of the gas delivery means can be achieved, and noise emitted by the gas delivery means can be reduced.

[0005] With the blower according to the invention, a mass allocation on the gas delivery means projected onto a plane perpendicular to the axis of rotation of the gas delivery means is balanced within the tolerance range of production-induced imbalance. This prevents runout caused by the selected mass distribution or an outward and inward thrashing by the gas delivery means in the radial direction and noise emitted as a result.

[0006] In an advantageous embodiment of the invention, torque is effected by at least two balancing masses located in offset positions in the circumferential direction, one of which is located before and the other of which is located after a center of gravity of the gas delivery means in the axial direction. Torque can be achieved using a particularly simple design and in cost-effective fashion.

[0007] Advantageously, two axially separated balancing masses are situated offset by 180° in relation to each other, which allows the balancing masses to be designed the same. If balancing masses are of equal size and their radial distance from the axis of rotation is the same, the gas delivery means is balanced in the plane perpendicular to its axis of rotation, with the exception of imbalance resulting from production tolerances. The torque components of the individual balancing masses not only add up vectorially, but, with this geometry, according to their percentage as well.

[0008] The balancing masses are preferably arranged on a central fixture of vanes of the gas delivery means. With a long axial design, the balancing masses can be separated by a wide axial distance. Sufficiently high torque can be easily effected. The gas delivery means is particularly stable on this central fixture of vanes. Disturbing twisting of the gas delivery means resulting from force acting on the balancing masses can be prevented. Moreover, the attachment site on a central fixture of vanes is particularly favorable in terms of aerodynamics.

[0009] In an advantageous embodiment of the invention, the balancing masses are located on the gas delivery means in moveable fashion, in the axial direction in particular. In principle, the balancing masses could also be designed to be moveable in the radial and/or circumferential direction. Using moveable balancing masses, torque can be adjusting throughout the life of the blower. Depending on its state of wear, the blower can always be adjusted so that noise is minimized.

[0010] The mass distribution that effects torque can also be advantageously integrated on the gas delivery means, however. A separate working step, such as the attachment of balancing masses, is eliminated. This is possible, preferably using production engineering, when the gas delivery means is an injection-molded part, and the mass distribution is integrally extruded on the gas delivery means. Analogous to the attachment of individual balancing masses, delimited areas can also be integrally extruded on the gas delivery means as balancing masses.

[0011] In an advantageous embodiment of the invention, the gas delivery means is designed as a fan wheel. Fan wheels are preferred over ventilators because they produce a uniform air flow, and their design is simple compared to that of turbines.

[0012] The means of attaining the solution according to the invention can be used in numerous different blowers appearing reasonable to one skilled in the art. The means of attaining the solution is suited particularly advantageously for use with a blower for an internal combustion engine radiator, which, as a rule, produces a great deal of structure-borne noise.

BRIEF DESCRIPTION OF THE DRAWING

[0013] Further advantages result from the following description of the drawing. An exemplary embodiment of the invention is presented in the drawings. The drawing, the description, and the claims contain numerous features in combination. One skilled in the art will advantageously consider them individually as well and combine them into reasonable further combinations.

[0014]FIG. 1 shows a front view of a fan wheel of an internal combustion engine radiator blower having two balancing masses located on the fan wheel hub,

[0015]FIG. 2 shows a view along the line II-II in FIG. 1, and

[0016]FIG. 3 shows a schematic diagram of the arrangement of balancing masses in a plane containing the fan wheel axis.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENT

[0017]FIG. 1 shows a gas delivery means in the form of a fan wheel 10 of an internal combustion engine radiator blower. Seven vanes 14 are located on a central wheel hub 12. The vanes 14 are connected by a ring 16 on their radially outer ends. Due to their shape, the seven vanes 14 generate a uniform air flow through a radiator (not shown) of an internal combustion engine of a motor vehicle.

[0018] Two balancing masses 20, 22 are located on a cylinder jacket surface 18 of the wheel hub 12. Viewed in the axial direction, the balancing masses 20, 22 are located diametrically opposed, or offset 180° in relation to each other in the circumferential direction. As a result of this, the fan wheel 10 is balanced in a plane perpendicular to its axis of rotation 26, with the exception of imbalance due to production tolerances. That is, the center of gravity 24 of the fan wheel 10 lies on its axis. This prevents the fan wheel 10 from thrashing back and forth in the radial direction during rotation. One balancing mass 20 is located before and one balancing mass 22 is located after the center of gravity 24 of the gas delivery means 10 in the axial direction (FIG. 2).

[0019] When the fan wheel 10 rotates, centrifugal forces {overscore (F)}₁ and {overscore (F)}₂ act upon the balancing masses 20, 22. The vector product of the position vector {overscore (s)}₁ or {overscore (s)}₂ of the distance of the respective balancing mass 20, 22 from the center of gravity 24 and this force {overscore (F)}₁, {overscore (F)}₂ yields a torque {overscore (M)}₁ or {overscore (M)}₂ effected by the respective balancing mass 20, 22. The total torque of both balancing masses 20, 22 is therefore calculated as follows:

{overscore (M)}={overscore (M)} ₁ +{overscore (M)} ₂ ={overscore (s)} ₁ ×{overscore (F)} ₁ +{overscore (s)} ₂ ×{overscore (F)} ₂

[0020] As illustrated in FIG. 3, the torque is situated perpendicular to the axis of rotation 26 of the fan wheel 10. As a result, the fan wheel 10 tilts downward slightly within its bearing clearance. The bearing of the fan wheel 10 is therefore always under preload during a rotational motion. Noise emitted from the fan wheel 10 is reduced.

REFERENCE NUMERALS

[0021]10 Fan wheel

[0022]12 Wheel hub

[0023]14 Vane

[0024]16 Ring

[0025]18 Cylinder jacket surface

[0026]20 Balancing mass

[0027]22 Balancing mass

[0028]24 Center of gravity

[0029]26 Axis of rotation

[0030] {overscore (F)}₁ Centrifugal force

[0031] {overscore (F)}₂ Centrifugal force

[0032] {overscore (s)}₁ Position vector

[0033] {overscore (s)}₂ Position vector

[0034] {overscore (M)}₁ Torque

[0035] {overscore (M)}₂ Torque

[0036] {overscore (M)} Torque 

What is claimed is:
 1. A blower having a rotatable gas delivery means (10), wherein the gas delivery means (10) comprises a mass distribution that generates a predefined torque perpendicular to the axis of rotation (26) when the gas delivery (10) means rotates.
 2. The blower according to claim 1, wherein a mass allocation on the gas delivery means (10) projected onto a plane perpendicular to the axis of rotation (26) is balanced within the tolerance range of production-induced imbalance.
 3. The blower according to claim 1 or 2, wherein the torque is effected by at least two balancing masses (20, 22) situated offset in the circumferential direction, one of which is located before and the other of which is located after the center of gravity (24) of the gas delivery means (10) in the axial direction.
 4. The blower according to claim 3, wherein the balancing masses (20, 22) are located offset by 180° in relation to each other.
 5. The blower according to claim 3 or 4, wherein the balancing masses (20, 22) are located on a central fixture of vanes (14) of the gas delivery means (10).
 6. The blower according to one of the claims 3 through 5, wherein the balancing masses (20, 22) are moveable.
 7. The blower according to one of the preceding claims, wherein the mass distribution effecting the torque is integral with the gas delivery means (10).
 8. The blower according to claim 7, wherein the gas delivery means (10) is an injection-molded part, and the mass distribution is integrally extruded on the gas delivery means (10).
 9. The blower according to one of the preceding claims, wherein the gas delivery means (10) is a fan wheel. 